The reduction of carbon dioxide emissions is an urgent challenge, and the adoption of clean energy technologies is being accelerated worldwide. To support hydrogen energy utilization, we have focused on the development of materials for use in hydrogen environments and have developed a method for directly observing hydrogen behavior within materials. The operando hydrogen microscope （figure1）obtains spatial information on hydrogen residing on a surface by utilizing electron-stimulated desorption (ESD). We have independently developed the instrument. By supplying hydrogen from the back side of a membrane type specimen, it enables visualization of hydrogen behavior that reflects the material's microstructure. This technique has been applied to the study of highly hydrogen-permeable materials and hydrogen barrier films.

Figure 1. Photograph and schematic diagram of the hydrogen microscope. The instrument consists of a high-resolution electron microscope (Elionix Inc.) equipped with hydrogen introduction and detection systems. The vacuum chamber and pumping system were modified to enable operation under ultrahigh-vacuum conditions.